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SubtleHustle

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#1
Hi, so I am tired of buying carbide inserts, and want to teach myself to grind hss blanks instead. Couple questions...what material to use, and where is a good source for good quality, low cost blanks? Also, what reference material can you all suggest, to learn the proper grinding methods? Thanks for any help. Also, I aim using a phase 2 qctp(axa), what size should I look at. 3/8? 1/2?
 

RJSakowski

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#2
Hi, so I am tired of buying carbide inserts, and want to teach myself to grind hss blanks instead. Couple questions...what material to use, and where is a good source for good quality, low cost blanks? Also, what reference material can you all suggest, to learn the proper grinding methods? Thanks for any help. Also, I aim using a phase 2 qctp(axa), what size should I look at. 3/8? 1/2?
It takes a lot more grinding to shape a 1/2" blank than a 3/8". You gain rigidity with the 1/2" blank but it is not that much of a deal for an AXA QCTP.

I actually use blanks down to 1/8". If you're making a tool for cutting a .030 snap ring , there is a lot less material to grind away. 1/4" blanks are useful too. My most used sizes on my 602 are 3/8" and 1/4".

As to material. M2 HSS is the common choice. If you are looking for a tougher tool, choose cobalt blanks. They are more expensive but perform better. For practicing, it has been suggested that you use ordinary mild steel key stock as it is easier to grind. and less expensive. another suggestion has been to make some visual aides from a piece of 2 x 2 wood. It is easier to see the various angles on the larger sample and easier to cut to form. Use them as a reference when you're grinding your tools.

Finally, when grinding tools, I mount the tool in a spare tool holder. It is easier to manage while grinding and it doesn't heat up as fast and you have better control when grinding the various angles.
 

Ulma Doctor

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#3
i generally get the biggest HSS blanks my toolholders can hold, and a few smaller 1/4" and 5/16" ones for unforeseen work.
i prefer old American HSS and Cobalt HSS blanks, like Rexcel and Mo-Max,
but the imported stuff has gained a lot of quality in the past few years.

I'd have a look at Shars, All Industrial Tool Supply, JT Machinery, and Ebay, all these sources have what you need.

Have a look at this well written and informative thread @mikey posted...
https://www.hobby-machinist.com/threads/models-for-grinding-hss-lathe-tools.62111/

South Bend's How to run a lathe is also a very good book to become familiar with , even if you don't have a South Bend lathe

Tom's Techniques on YouTube is also a bevy of good info
That Lazy Machinist is really good and informative too on YouTube
 

SubtleHustle

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It takes a lot more grinding to shape a 1/2" blank than a 3/8". You gain rigidity with the 1/2" blank but it is not that much of a deal for an AXA QCTP.

I actually use blanks down to 1/8". If you're making a tool for cutting a .030 snap ring , there is a lot less material to grind away. 1/4" blanks are useful too. My most used sizes on my 602 are 3/8" and 1/4".

As to material. M2 HSS is the common choice. If you are looking for a tougher tool, choose cobalt blanks. They are more expensive but perform better. For practicing, it has been suggested that you use ordinary mild steel key stock as it is easier to grind. and less expensive. another suggestion has been to make some visual aides from a piece of 2 x 2 wood. It is easier to see the various angles on the larger sample and easier to cut to form. Use them as a reference when you're grinding your tools.

Finally, when grinding tools, I mount the tool in a spare tool holder. It is easier to manage while grinding and it doesn't heat up as fast and you have better control when grinding the various angles.
Great info! Have a good source, or all they all basically the same, except the price? Also, what's some good learning material? Thanks again for the tips!
 

SubtleHustle

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i generally get the biggest HSS blanks my toolholders can hold, and a few smaller 1/4" and 5/16" ones for unforeseen work.
i prefer old American HSS and Cobalt HSS blanks, like Rexcel and Mo-Max,
but the imported stuff has gained a lot of quality in the past few years.

I'd have a look at Shars, All Industrial Tool Supply, JT Machinery, and Ebay, all these sources have what you need.

Have a look at this well written and informative thread @mikey posted...
https://www.hobby-machinist.com/threads/models-for-grinding-hss-lathe-tools.62111/

South Bend's How to run a lathe is also a very good book to become familiar with , even if you don't have a South Bend lathe

Tom's Techniques on YouTube is also a bevy of good info
That Lazy Machinist is really good and informative too on YouTube
Perfect! Just what I was looking for! Thanks!
 

Bob Korves

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#6
Since throw away carbide inserts and brazed carbide tooling have taken over the machining world, high speed steel (HSS) has become a niche item. Sad, because it is more generally useful than inserts are. It is also tough, and can easily be ground to whatever shape you can imagine. Places like eBay, auctions, machine shop closeouts, and Craigslist are good sources of bulk HSS lots, some of it new. You can sometimes find them in bucket sized quantities, covered in grime, for very little money. I have probably 100 pounds of HSS, bought less than one pound of it new. I certainly do not have $50 in the entire pile. A degrease followed by a soak in Evapo-rust makes them look like new. They are now sorted by size and style, ready to use or grind.

But wait, it gets even better! Used HSS is often already ground into tools, at least on one end. That usually takes away most to all of the time and effort required to rough in the tool blank into something resembling a tool. With used HSS, you can just grind it sharp again or modify one that is close into what you need. Another bonus is that the older USA made HSS is generally higher quality that the stuff now being imported from Asia. And it costs less, as much at 90% less, or even less than that if you shop wisely.

One more thing. It is worthwhile looking at the tool grinds that old timers, many of them now long dead and gone, put on the HSS. You can learn a lot by just looking at them and trying to guess what they were used for. It makes you think of all the ways that cutters can be shaped to do a job best. Even really short pieces of HSS are not junk, they are insertable bits for boring bars, fly cutters, and the like. You can make your own tooling to hold those short cutters and have a nice assortment of boring bars and other tooling at an extremely low cost, and you will learn along the way.

If you are doing production work for money, trying to get product out the door, then HSS may be too time consuming for you to use. Same when cutting really hard stuff. If you might be a hobbyist, like most of us on this forum, HSS is the best bet for most of your general cutting needs, and is also a good learning tool, teaching you what works and what does not work for a given job. There is lots of good information on this forum and on the internet for making HSS tools and working with them. Many newcomers to this sport leapfrog over learning about HSS directly to carbide inserts, but they are doing themselves a big disservice.
 

Cadillac

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#7
Bob is right on about buying used tooling. Ive bought shoe boxes full some ground some new and a spectrum of grades. Touching up the ground ones teaches you the angles so the works been done already. Shops have mostly converted to carbide so five gallon buckets full can be had for scrap prices.
 

ttabbal

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#8
When I started, I was planning to start with inserts as it seemed like the "way it's done". And if you're a production shop, that is the best way most of the time. Particularly if you have a big, fast, machine. For the smaller and slower machines hobby users tend to have access to, HSS is great stuff.

Most of my tools are ground from a box of 50 M2 HSS bits made in China. They work fine most of the time and are a great way to get started if you can't find buckets of it floating around. I still have most of the bits new in the box as you can keep sharpening them so you don't need a ton of them. I have an 11x27 lathe and AXA toolpost. I use mostly 3/8" HSS as it's more than rigid enough for my machine. I also have a few M42 cobalt bits and some Tungsten containing bits. My most commonly used tool right now is a simple square tool in 3/8 M42. Nice clean cuts on most things.

The insert tools are nice to have around when you need the abilities they bring to the table. For example, I have some material here that's hard enough that it eats HSS bits. Good inserts cut it very nicely. The Banggood inserts did alright, but the Iscar inserts cut it like a dream. 304 Stainless works well with them too.
 

homebrewed

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#9
Also check out Victor Machinery (@victornet.com) for HSS and cobalt blanks. I bought some cobalt 5/16" blanks there for about the same price other vendors were selling HSS. Since Enco was assimilated (Borg style), I've been buying more & more from Victor.
 

kev74

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#10
I've gotten a bunch of blanks and previously ground tooling from eBay auctions. Most came in lots with other tooling.
 

Bob Korves

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#11
It is also obvious after you think about it or see it, but HSS can easily be ground with the same or different cutting edges on both ends of the blank, double the tooling for your money! And when they get dull, you just grind them a bit more to get them sharp again, or modify them as needed for a special job. You do not need to wait for a special insert (and maybe a holder) to arrive from a tool vendor to get the job at hand done!
 

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#12
Hi Guys,

Here in the UK scrap yards, I think that you call them salvage yards, often have bucket loads of HSS tool bits that have been disposed of by engineering shops, particularly those that have turned to carbide insert tooling.

One I visit quite regularly has 40 gallon drums often full to the top of scrap carbide and scrap HSS. Its a long time since I purchased any new sticks of HSS. Most of mine is M42 cobalt.
 

SubtleHustle

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It is also obvious after you think about it or see it, but HSS can easily be ground with the same or different cutting edges on both ends of the blank, double the tooling for your money! And when they get dull, you just grind them a bit more to get them sharp again, or modify them as needed for a special job. You do not need to wait for a special insert (and maybe a holder) to arrive from a tool vendor to get the job at hand done!
Makes sense! Thanks Bob, you've always given me good advise, and I appreciate it.
 

benmychree

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Sometimes, HSS tool bits have a gash ground on one end; grind your tool on the other end, not the gashed end, it marks the gate end that the bits were cast from, where there might be defects lurking. Bob's suggestion about grinding tools on both ends, brought this to mind. The gash thing is likely to be seen in old stock tool bits, less likely on new bits.
On my 9" Monarch lathe with AXA tool post, I mostly use 5/16" square tool bits, 1/4"bits are not so easy to clamp down with the setscrews if the bit is held right on the edge of the holder, and yes, 3/8" bits take considerably more grinding than smaller bits, Using 7/16 or 1/2" bits on a small lathe compounds this considerably -----
 

mikey

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#15
I agree with RJ - start with mild steel keystock from the hardware store and grind on that until you can grind a decent tool with control. It is far, far, far easier to learn this skill that way.

This deal is still active on ebay: https://www.ebay.com/itm/50pcs-3-8-...=item486dc82c77:g:ITMAAOSwRLZUCgJb:rk:21:pf:0

50 bits of 3/8" M2 HSS for $64.00! You would be hard pressed to find a better deal no matter where you shop. This is Chinese HSS but it works pretty okay. It is not of the quality you will find from good suppliers from the US or Europe but it is more than adequate for a hobby shop.

I have or had a whole bunch of bits ground by machinists of the past and it is fascinating to imagine what job they ground the tool for. Some of them are pretty imaginative; most were crude, and some would barely cut Delrin. Nowadays, I will personally not buy pre-ground tools; once you fix the previous grind the tool is usually too short to safely work with on the grinder.
 

SubtleHustle

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I agree with RJ - start with mild steel keystock from the hardware store and grind on that until you can grind a decent tool with control. It is far, far, far easier to learn this skill that way.

This deal is still active on ebay: https://www.ebay.com/itm/50pcs-3-8-...=item486dc82c77:g:ITMAAOSwRLZUCgJb:rk:21:pf:0

50 bits of 3/8" M2 HSS for $64.00! You would be hard pressed to find a better deal no matter where you shop. This is Chinese HSS but it works pretty okay. It is not of the quality you will find from good suppliers from the US or Europe but it is more than adequate for a hobby shop.

I have or had a whole bunch of bits ground by machinists of the past and it is fascinating to imagine what job they ground the tool for. Some of them are pretty imaginative; most were crude, and some would barely cut Delrin. Nowadays, I will personally not buy pre-ground tools; once you fix the previous grind the tool is usually too short to safely work with on the grinder.
Thanks mikey! Just ordered 50 of those, I will check with the local hardware store for 3/8 key stock tonight, hopefully they have some in stock, that I can practise on.
 

mikey

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Thanks mikey! Just ordered 50 of those, I will check with the local hardware store for 3/8 key stock tonight, hopefully they have some in stock, that I can practise on.
Join us on the model tools thread and we'll help you along.
 

GL

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#18
Interesting post, similar argument in my own head of late. I ran my old Craftsman 12x36 for probably 20 years before I "had" to get a QCTP and carbide insert tools. New 1340GT and I started over again with a QCTP and insert tools, because that's what you are supposed to get and they are cool. I still have the two 1/4" HSS tool blanks for the old lathe, and they are not much shorter than when I got them. The 4 way tool post that came with the new lathe is kind of looking interesting too. Been watching videos and reading the voluminous arguments for and against both. Bought a few HSS blanks the other day to start grinding my own again. All that was old is new again. Will not dismiss the bucket of HSS next time I see one, although it seems proven that a few will last nearly forever. Ground blanks also make good parallels by the way -I have a few I inherited along the way that are much too large for anything I will ever own, but use them often in setups.
 

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#19
Hi Guys,

I agree that they make good cheap parallels ! But just be a bit careful, whilst the sides are very accurately parallel, they are not always dead square. Many times I've found that a nominal 10 mm is 9.80 by 10.0, and unless you either compare them or measure them, you could make an error if relying on them to be square.

When I find ones like that I use a red marker and put a line or size on the large side.
 

Bob Korves

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#20
HSS blanks are quite useful for setups on the milling machine.
 

RJSakowski

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#21
One thing to consider is that old time lathe tools were ground for use with lantern style tool holders. The tool holders generally had a built-in rake angle so the top surface could be used as-is. Modern QCTP and 4-way tool holders present the tool to the work horizontally so the back rake must be ground into the tool. Also affected is the end relief. Tools used in the lantern style holder needed more relief ground into the tool because of the lantern style holder.

When grinding tools, it is important to look at how the tool is presented to the work. The rotating work sees the tool in a plane containing the axis of rotation and the cutting edge of the tool. Normally, that plane is horizontal (parallel to the cross feed ways as this ensures that the cutting edge will pass through the center of the work and that movement of the cross feed is exactly 1/2 the reduction in diameter. However, changing the cutter height slightly can have benefits. Raising cutter height above the centerline has the effect of increasing back rake and decreasing the end relief.

Each lathe has its own characteristics. The available power, and rigidity of the lathe play an important part in lathe tool design. Large lathes usually have power to burn and are massive. What works for them will not necessarily work for a small bench top lathe. This should be taken into consideration when grinding your tools. It would be very frustrating to grind a tool exactly like one known to work well for another lathe and find that it gives totally unsatisfactory results on your lathe. Use some of the principles as a starting point and do some experimenting for your particular best geometry.
 

Bob Korves

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One thing to consider is that old time lathe tools were ground for use with lantern style tool holders. The tool holders generally had a built-in rake angle so the top surface could be used as-is. Modern QCTP and 4-way tool holders present the tool to the work horizontally so the back rake must be ground into the tool. Also affected is the end relief. Tools used in the lantern style holder needed more relief ground into the tool because of the lantern style holder.

When grinding tools, it is important to look at how the tool is presented to the work. The rotating work sees the tool in a plane containing the axis of rotation and the cutting edge of the tool. Normally, that plane is horizontal (parallel to the cross feed ways as this ensures that the cutting edge will pass through the center of the work and that movement of the cross feed is exactly 1/2 the reduction in diameter. However, changing the cutter height slightly can have benefits. Raising cutter height above the centerline has the effect of increasing back rake and decreasing the end relief.

Each lathe has its own characteristics. The available power, and rigidity of the lathe play an important part in lathe tool design. Large lathes usually have power to burn and are massive. What works for them will not necessarily work for a small bench top lathe. This should be taken into consideration when grinding your tools. It would be very frustrating to grind a tool exactly like one known to work well for another lathe and find that it gives totally unsatisfactory results on your lathe. Use some of the principles as a starting point and do some experimenting for your particular best geometry.
Great post, RJ!
 

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#23
I have very limited experience. Recently, I was given a wooden box of old school carbide tipped tools with a shaper I bought. Most or all had chipped or missing carbide. I wondered their value until I tried one on the grinder -very hard stuff and difficult to even grind. I looked through box and found one had back end ground into a shaper bit. I'm not sure if its tool steel or HSS but does a real nice job in my 1920s? Ohio shaper. I'm not saying anyone should hunt for broken carbide tipped tools, but I wouldn't necessarily scrap them either.

It's my understanding, HSS wasn't widely used until the 1930s, so tool steel isn't necessarily a bad choice for home shop use. I assume it has less heat and wear tolerance.
 

mikey

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#24
Actually, the first tool that was truly classified as HSS was T-1, formulated by Crucible in 1910. The M-class of HSS came out in the 1930's.

I would guess that the tool shank on your carbide tools is some kind of low to medium carbon steel, not tool steel. I may be wrong but I would think that using tool steel for a tool shank would be economically prohibitive. Some medium carbon steels will work harden with the heat of grinding and that might allow it to be used as a cutting tool, albeit with limited edge life.
 

Janderso

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#26
Bob, John York and RJ are mentors worth listening to.
This forum has some very smart and experienced consultants IMHO
And, they are willing to share their skills willingly.
God bless us all.
Sorry, I got carried away.
 

benmychree

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Actually, the first tool that was truly classified as HSS was T-1, formulated by Crucible in 1910. The M-class of HSS came out in the 1930's.

I would guess that the tool shank on your carbide tools is some kind of low to medium carbon steel, not tool steel. I may be wrong but I would think that using tool steel for a tool shank would be economically prohibitive. Some medium carbon steels will work harden with the heat of grinding and that might allow it to be used as a cutting tool, albeit with limited edge life.
Brazed on tool shanks are something like 1040 or 1045 carbon steel, they are hardenable to a fair degree.
 

middle.road

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#28
Sometimes, HSS tool bits have a gash ground on one end; grind your tool on the other end, not the gashed end, it marks the gate end that the bits were cast from, where there might be defects lurking. Bob's suggestion about grinding tools on both ends, brought this to mind. The gash thing is likely to be seen in old stock tool bits, less likely on new bits.
Do you mean the vertical gash on some bits?
 

benmychree

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I have seen bits that had a single gash, and some with a cross cut into the end, like with a cut off wheel or some such thing. Vertical: define vertical on a square tool bit --- If the bit were cut on an angle on the ends, as they frequently were, if the bit was viewed with the angle sloping down , the gash would be vertical.
 

mmcmdl

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#30
Most likely someone ground a chip breaker into it . Cutting plastic at high speed with that grooved nose will land your chips directly into a trash can at 5 ft away !
 
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